首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1232篇
  免费   48篇
  国内免费   12篇
耳鼻咽喉   26篇
儿科学   61篇
妇产科学   34篇
基础医学   71篇
口腔科学   54篇
临床医学   105篇
内科学   329篇
皮肤病学   24篇
神经病学   54篇
特种医学   86篇
外科学   321篇
综合类   19篇
预防医学   17篇
眼科学   31篇
药学   25篇
中国医学   3篇
肿瘤学   32篇
  2024年   3篇
  2023年   11篇
  2022年   25篇
  2021年   44篇
  2020年   19篇
  2019年   19篇
  2018年   30篇
  2017年   27篇
  2016年   30篇
  2015年   22篇
  2014年   37篇
  2013年   72篇
  2012年   69篇
  2011年   86篇
  2010年   46篇
  2009年   50篇
  2008年   81篇
  2007年   110篇
  2006年   86篇
  2005年   94篇
  2004年   64篇
  2003年   64篇
  2002年   56篇
  2001年   17篇
  2000年   9篇
  1999年   10篇
  1998年   7篇
  1997年   8篇
  1996年   4篇
  1995年   10篇
  1994年   10篇
  1993年   10篇
  1992年   11篇
  1991年   11篇
  1990年   10篇
  1989年   2篇
  1988年   4篇
  1987年   7篇
  1986年   3篇
  1985年   2篇
  1984年   1篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
  1974年   1篇
  1971年   1篇
  1970年   2篇
  1969年   2篇
  1961年   1篇
  1959年   1篇
排序方式: 共有1292条查询结果,搜索用时 15 毫秒
1.
2.
Brucellosis is a multisystemic disease that rarely leads to a fatal outcome. While reticuloendothelial system organs are mostly affected, peritonitis and posthepatitic cirrhosis are also complications of brucellosis, though they are very rare. Brucella spp. can also trigger immunological reactions. We report a case of brucellosis with peritonitis, renal failure and leucocytoclastic vasculitis caused by Brucella melitensis, which led to a fatal outcome. Brucellosis should be considered in the differential diagnosis of vasculitic diseases, especially in endemic areas.  相似文献   
3.
During the treatment of patients with renal failure or renal transplants the most important consideration is to eliminate sources of infection before and after the treatment. Acute or chronic oral infections or bacteraemias resulting from dental procedures may cause serious complications in these patients who already have lowered host resistance caused by immunosuppressant therapy. In order to determine the latest concepts from some international transplantation centres relating to the importance of and the effect of infective sources in the oral cavity, a survey form was prepared which included several questions related to oral foci of infection and renal transplantations.
Results obtained from 22 centres from 12 countries indicated that the majority of the centres included a dental examination in their routine protocol and required completion of any necessary dental treatment before transplantation. However, full agreement among all these centres on the necessity for dental examination as part of the protocol has not yet been reached.  相似文献   
4.
5.
6.
Eighteen strains of Campylobacter sputorum bv. paraureolyticus (isolated over a 12-month period from seven dairy cows contained in a single herd) were examined by resistotyping, and macrorestriction profiling using pulsed field gel electrophoresis (PFGE). The resistotypes of these strains were identical, although repeat testing indicated resistance to metronidazole was not a reliable trait for typing purposes. Five SmaI-derived genotypes were identified among the 18 strains. In 5 of 7 cows, isolates obtained from the same animal, but from different time periods, were genotypically indistinguishable, indicating persistence of infection. Macrorestriction profiles of 5 strains representing the 5 SmaI genotypes and 8 other strains of C. sputorum from various sources, were prepared using 4 endonucleases (SmaI, SalI, BamHI and KpnI). The only other strain of C. sputorum bv. paraureolyticus examined (a Canadian isolate from human faeces), was found to have a SmaI macrorestriction profile identical with one of the five clones isolated from the cattle. Moreover, SalI and BamHI profiles of all bv. paraureolyticus strains were similar, while digestion with KpnI was not observed. By contrast, the seven strains of C. sputorum bv. sputorum yielded various macrorestriction profiles with all the enzymes used, and features distinguishing the two biovars studied could be identified. This study indicates that C. sputorum can persist in cattle for at least 12 months and exhibits a clonal population genetic structure.  相似文献   
7.
OBJECTIVE: An evaluation of growth hormone (GH) testing for GH deficiency (GHD) in childhood is confounded by the lack of a world-wide consensus on the definition of GHD. Although a single GH test remains the most powerful biochemical tool in the evaluation of a child with growth failure, the test remains far from ideal. Withdrawal of somatostatin (SS) infusion is followed by a rebound rise of GH thought to be mediated by endogenous GH-releasing hormone (GHRH) function. This study was designed to compare the GH response to 90 min SS infusion in children with normal GH secretion versus children with GH deficiency. METHODS: Ten children with GHD and 10 healthy controls (NC) have been evaluated for GH response to somatostatin infusion withdrawal (SSIW) and compared with response of two provocative tests, glucagon plus propranolol test and L-Dopa test. All children received constant infusion of somatostatin for 90 min (3 microg/kg per h, Stilamin, Serono, Aubonne, Switzerland). In order to determine GH, blood samples were obtained 90 min before the SS infusion and 0, 15, 30, 45, 60, 75, and 90 min after the cessation of infusion. RESULTS: Growth hormone peak levels with SSIW were significantly lower in GH deficient children than in healthy children (2.5 +/- 1.2 ng/dL, vs 21.9 +/- 5.3 ng/dL, respectively, P < 0.01). No adverse effects were observed during or after somatostatin infusion. CONCLUSION: In the present study, SSIW elicited a significant GH rise in healthy children but not in children with GH deficiency. Although further controlled studies using more data are necessary to expand these findings, the results suggested that children with GH deficiency can be reliably discriminated from healthy children by SSIW.  相似文献   
8.
The present study is intended to retrospectively compare the short- and long-term outcomes of 3 different treatment methods in patients undergoing bariatric surgery and the variances in weight and nutritional parameters during the preoperative and postoperative periods. In this study, 534 patients who underwent laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-En-Y gastric bypass (LRYGB), and laparoscopic one anastomosis gastric bypass (LOAGB) between 2014 and 2021 were included. The sociodemographic and biodemographic characteristics of these patients, their weight losses and nutritional changes in the preoperative and postoperative periods, operative times, hospital stays, complications, and morbidity and mortality rates were retrospectively compared. There was a statistically significant difference between the surgical methods in the percentages of excess weight loss and total weight loss in the 1st and 3rd months. There were significant differences in the homeostasis model assessment of insulin resistance, folic acid, vitamin D, iron, ferritin, and parathyroid hormone levels (P < .05). All 3 techniques were found to be successful in facilitating weight loss at the end of the first year. LRYGB and LOAGB were found to be superior to LSG in terms of remission from diabetes during the first 6 months, whereas LSG was superior to the other methods in terms of nutritional deficiencies. Despite being more advantageous in terms of operative time, LSG and LOAGB were disadvantageous compared with the LRYGB technique because of the higher rates of leakage and mortality in the LSG technique and the higher rate of bile reflux in the LOAGB technique.  相似文献   
9.
目的 探讨冠脉介入诊疗中术者上肢暴露部位射线剂量与部位高度、术者站位、造影体位及物理防护强度之间的关系.方法 通过对仿真人体模型进行造影曝光,采集桡动脉途径时2位模拟术者左手、左上臂在不同防护条件、不同造影体位下的体表入射剂量率.采用T检验比较仅穿无袖铅衣时左手和左上臂间的体表入射剂量率及同一部位在两位术者间的体表入射...  相似文献   
10.
To determine whether the possible oxidative effect of methotrexate (Mtx) on ovary and to evaluate the effectiveness of alpha lipoic acid (ALA), which may be useful in many oxidative stress models.

Thirty-two female Wistar-albino rats were randomly divided into four groups; control group, alpha lipoic acid group (ALA 100?mg/kg, 10?days), multiple dose Mtx group (Mtx 1?mg/kg 1, 3, 5, 7?days) and Mtx and ALA group (Mtx 1?mg/kg 1, 3, 5, 7?days and ALA 100?mg/kg, 10?days). Serum total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI), tumor necrosis factor-alpha (TNF-α), tissue malondialdehyde (MDA) and activities of glutathione peroxidase (GSH-Px) and catalase (CAT) and anti-Mullerian hormone (AMH) and total ovarian follicle count were evaluated.

Mtx administration caused a significant decrease in TAS, a significant increase in TOS and OSI, a significant increase in MDA levels and a decrease in GSH-Px and CAT activity. Moreover the proinflammatory cytokine (TNF-α) was increased in the Mtx group. And AMH values and total follicle count were significantly decreased in Mtx group. However, ALA treatment reversed biochemical results and AMH levels and total follicle count.

Alpha lipoic acid ameliorates methotrexate induced oxidative damage of ovarian in rats.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号